I used a 3-3.2V 20ma LED, a 1W 1K ohm resistor followed by a .25W 50 ohm resistor to be able to tap power from the part fan which is 24V .5A. The light is on whenever the machine is on. The black wire on the fan plug is your negative, red is positive. I used solid wire and shoved the wires into the back of the connecter and secured it with heat shrink.
This is a fairly crude mock-up but it works well. I also made the the magnet holes 2.75mm depth instead of 3 because it works better with the cheap magnets I got on amazon. the tape one the back of the led was to stop some of the light bleed out the back.
The author remixed this model.
5mm led mount added and magnet holes depth decreased